Increased skeletal muscle acetylcholinesterase activity in porcine malignant hyperthermia (original) (raw)
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Molecular and cellular biochemistry, 1999
Meat quality of pigs is dependent on biochemical and biophysical processes in the time course post mortem (p.m.) and is associated with the intracellular Ca2+ homeostasis. However, there is little known about changes in the Ca2+ transporting proteins controlling the Ca2+ uptake of sarcoplasmic reticulum (SR) in the time course p.m. In this study changes in the Ca2+ transporting proteins were investigated in homogenates of longissimus muscles of 4 malignant hyperthermia susceptible (MHS) and 6 malignant hyperthermia resistant (MHR) Pietrain pigs. Muscle samples were obtained at different time intervals: biopsy 2 h prior slaughtering and from the carcass immediately after exsanguination (0 h), 45 min, 4 h, and 22 h p.m. The SR Ca2+ uptake rate was measured immediately after homogenization with closed calcium release channel (CRC), with opened CRC and without manipulation of CRC. Additionally the SR Ca2+ ATPase activity was determined. The results show: (i) The ability of SR to sequest...
Meat science, 1995
Energy metabolism of the biceps femoris muscle of normal and heterozygote malignant-hyperthermia pigs was studied post-mortem after in-vivo exposure to a combination of halothane and succinylcholine. The pigs were anaesthetized with halothane and subsequently captive-bolt-stunned immediately after intravenous administration of succinylcholine. Cardiac arrest occurred within one minute after the depolarizing neuromuscular blocking with succinylcholine. During the following 2-5 hours post mortem, the level of several metabolites, reflecting the rate of muscle glycogenolysis and glycolysis, was measured by analytical biochemical techniques and by in situ (31)P-NMR spectroscopy. Both techniques demonstrated more than three-fold-accelerated PCr decay, matched by a similar increase of P(i) in heterozygotes compared with normal pigs. The rate of pH decrease and of lactate accumulation was also three to five times higher in the heterozygotes, all-in-all demonstrating a significantly increas...
Biochimica et Biophysica Acta (BBA) - Biomembranes, 1984
The time-course of Ca z+ release from sarcoplasmic reticulum isolated from muscles of normal pigs and those of pigs susceptible to malignant hyperthermia were investigated using stopped-flow spectrophotometry and arsenazo II1 as a Ca 2+ indicator. Several methods were used to trigger Ca 2+ release: (a) addition of halothane (e.g., 0.2 mM); (b) an increase of extravesicular Ca 2+ concentration ([Ca20 + ]); (c) a combination of (a) and (b), and (d) replacement of ions (potassium gluconate with choline chloride) to produce membrane depolarization. The initial rates of Ca 2+ release induced by either halothane or Ca 2+ alone, or both, are at least 70% higher in malignant hyperthermic sarcoplasmic reticulum than in normal. The amount of Ca z+ released by halothane at low [Ca~ + ] in malignant hyperthermic sarcoplasmic reticulum is about twice as large as in normal sarcoplasmic reticulum. Membrane depolarization led to biphasic Ca 2+ release in both malignant hyperthermic and normal sarcoplasmic reticulum, the rate constant of the rapid phase of Ca 2+ release induced by membrane depolarization being significantly higher in malignant hyperthermic sarcoplasmic reticulum (k-83 s-t) than in normal (k = 37 s-m). Thus, all types of Ca z+ release investigated (a, b, c and d) have higher rates in malignant hyperthermic sarcoplasmic reticulum than normal sarcoplasmic reticulum. These results suggest that the putative Ca 2 + release channels located in the sarcoplasmic reticulum are altered in malignant hyperthermic sarcoplasmic reticulum.
High skeletal muscle adenylate cyclase in malignant hyperthermia
Journal of Clinical Investigation, 1981
hyperthermia occurs in humans with several congenital myopathies, usually in response to general anesthesia. Commonly, individuals who develop this syndrome lack symptoms of muscle disease, and their muscle lacks specific pathological changes. A biochemical marker for this myopathy has not previously been available; we found activity of adenylate cyclase and content of cyclic AMP to be abnormally high in skeletal muscle. Secondary modification of protein phosphorylation could explain observed abnormalities of phosphorylase activation and sarcoplasmic reticulum function.
Myoplasmic free [Ca2+] during a malignant hyperthermia episode in swine
Muscle & Nerve, 1988
Malignant hyperthermia (MH) is a genetic syndrome usually initiated by exposure to volatile anesthetic agents or depolarizing neuromuscular blocking agents. We have used Ca'+-selective microelectrodes to measure in vivo the intracellular ionized calcium ([Ca"],) in skeletal muscle fibers of MH-susceptible swines before and during hyperthermic episodes and also after dantrolene administration. The animals were anesthetized with thiopendl and fentanyl and maintained with a mixture of nitrous oxide (66%) and oxygen (34%). The malignant hyperthermic episode was triggered by exposure to halothane. Determinations of [Ca''], during the episode show an increase from 0.44 2 0.01 pM 5 SEM, n = 20) to 8.44 2 0.68 pM (mean -t SEM, R = 10). Administration of dantrolene (2 mg/kg) during the hyperthermic episode reduces [Ca2+], to 0.17 + 0.01 pM (mean 2 SEM, n = 10) and reverses the clinical symptoms. These results show that the MH episode is associated with an increase in the myoplasmic free Ca2+ concentration and that the therapeutic effect of dantrolene is related to a decrease in [Ca' t]l.
Temperature-dependent abnormalities of the erythrocyte membrane in porcine malignant hyperthermia
Biochemical medicine and metabolic biology, 1987
The temperature dependence of ATPase activities and stearic acid spin label motion in red blood cells of normal and MH-susceptible pigs have been examined. Arrhenius plots of red blood cell ghost Ca-ATPase and calmodulin-stimulable Ca-ATPase activities were identical for both normal and MH erythrocyte ghosts. Arrhenius plots of Mg-ATPase activity exhibited a break (defined as a change in slope) at 24 degrees C in both MH and normal erythrocyte ghosts. However, below 24 degrees C the apparent activation energy for this activity was less in MH than normal ghosts. To determine whether breaks in ATPase Arrhenius plots could be correlated with changes in the physical state of the red blood cell membrane, the spin label 16-doxyl-stearate was introduced into the bilayer of both erythrocyte ghosts and red blood cells. With both ghosts and intact cells, at each temperature examined, the mobility of the probe in the lipid bilayer, as measured by electron paramagnetic resonance, was greater in...
Abnormal rapid Ca2+ release from sarcoplasmic reticulum of malignant hyperthermia susceptible pigs
Biochimica et Biophysica Acta (BBA) - Biomembranes, 1991
Using the rapid filtration technique to investigate Ca z+ movements across the sarcoglasmic reticuinm (SRI membrane, we compare the initial phases of Ca 2+ release and Ca ~+ ~tltake in malignant hyperthermia susceptible (MHS) and nmmal (N) pig SR vesicles. Ca z+ release is measured from passively loaded SR vesicles. MIlS SR vesicles present a 2-fold increase in the initial rate of calcium release induced by 0.3 .ttM Ca z + (20.1 4-2.1 vs. 6.3 4-2.6 nmul mg-i s-i). Maximal Ca z+ release is obtained with 3 pM Ca 2÷. At this optimal concentration, rate of Ca 2÷ efflux in absence of ATP is 55 and 25 nmol mg-t s-i for MHS and N SR, respectively. CaZ+-induced Ca 2÷ release is inhibited by Mg 2÷ in a dose-dependent manner for both MIlS and N pig SR vesicles (Kt/, " = 0.2 mM). Caffeine (5 raM) and halothene (0.01% v/v) increase the Ca 2÷ sensitivity of CaZ÷-induced Ca z÷ release. ATP (5 mM) strongly enhances the rate of Ca 2÷ effinx (to about 20-40-fold in both MIlS and N pig SR vesicles). Furthernmre, both types ol vesicles do not differ in their high-aflinity site for ryanodine (K d = 12 nM and Bm~ = 6 pmol/mg), lipid content, ATPase activity and initial rate of Ca 2÷ uptake (0.948 4. 0.034 vs. 0.835 4. 0.130 pmol mg-i rain-I for MHS and N SIL, respectively). Our results show that MH syndrome is associated to a higher rate of Ca 2+ release in the earliest phase of the calcium efflux.
Malignant hyperthermia: A runaway thermogenic futile cycle at the sodium channel level
Malignant Hyperthermia (“MH”)—the rapid onset of extremely high fever with muscle rigidity—is caused by a runaway heat production futile cycle mediated via the sodium channels at the myoneural receptor sites. MH is not triggered by non-depolarizing muscle relaxants; however, depolarizing muscle relaxants may trigger it [1]. Here we present a de novo hypothesis of how MH is triggered and develops. We believe that the acetylcholine receptor/sodium channels in the muscles of MH susceptible pigs initiate MH by allowing an increased flux of sodium ions when it is depolarized by acetylcholine or other depolarizing agents, such as succinylcholine and Halothane. Our theory is consistent with our observations of the effects of general anesthetics over twenty years. Succinylcholine is a depolarizing agent that is a potent MH trigger. Acetylcholine, the natural depolarizing muscle activator, may trigger MH if the susceptible patient or animal is exposed to sufficient stress, i.e., during strenuous activity, such as transport, fighting, breeding, etc. Halothane apparently destabilizes the myoneural sodium channels, which rapidly induces MH. The increased sodium channel activity releases heat with cascades that further releases of heat which results in the rapid onset of MH. MH susceptible pigs have increased action potential amplitudes at their myoneural junctions that are abnormally long in duration. This increased activity is thought to induce hypertrophy of muscle mass, increase metabolic rate, and cause other physical manifestations. When slaughtered, this increased metabolic activity causes the rapid post mortem release of heat in the muscles of MH susceptible pigs and, at the same time, the accumulation of low acidity, all of which denatures the muscle proteins to result in a pale, soft, exudative, pork meat considered to be of lesser quality for human consumption. The potency of inhalation anesthetics as a MH triggers varies widely. The inhalation anesthetic Halothane is a strong trigger of MH, causing MH within minutes of exposure. In contrast, the anesthetic Sevoflurane is a very weak trigger of MH, requiring several hours of inhalation exposure to trigger MH. Because of this, changing from Halothane to Sevoflurane as the general anesthetic of choice for surgeries in hospitals in the Greater Kansas City area during 1994 to 2006 led to an 11-fold decrease in the incidence of MH, from 1:50,000 to 1:550,000 [11]. One non-depolarizing muscle relaxant, Organon 9426 (“Rocuronium”) temporarily prevents MH in MH susceptible pigs when they are given sufficient dosages of it before being challenged with either Halothane or succinylcholine. Binding Rocuronium to the myoneural receptor sites apparently stabilizes them, thereby preventing increased sodium channel activity, and resulting MH. However, other non-depolarizing muscle relaxants do not have this protective effect— for examples Vecuronium, Arduan, and Organon 9616 do not. Uncoupling of mitochondria is not the source of accelerated heat production in MH susceptible pigs, as heart, liver, and skeletal muscle mitochondria isolated from MH susceptible pigs are all competent.
Ca2+ Influx via the Na+/Ca2+ Exchanger Is Enhanced in Malignant Hyperthermia Skeletal Muscle
Journal of Biological Chemistry, 2014
Background: Dysregulation of Ca 2ϩ homeostasis have been described in malignant hyperthermia (MH). Results: Na ϩ /Ca 2ϩ exchanger (NCX3) reverse mode activity is enhanced in MH muscles and it contributes to resting intracellular calcium concentration and Ca 2ϩ transients induced by high [K ϩ ] e and by halothane. Conclusion: NCX3 reverse mode activity is increased in MH muscle. Significance: Understanding mechanisms influencing Ca 2ϩ dynamics in MH muscle.
Malignant hyperthermia (MH) in swine is a consequence of porcine stress syndrome (PSS) caused by a mutation in the ryanodine receptor gene (ryr1) which plays a main role in Ca 2+ transport in muscle cells. There are few critical points in biochemical pathways that can be affected by the presence of MH. This study was designed to match the different genotypes for MH with some biochemical parameters which can be related to it. One hundred and fourteen animals previously genotyped for MH using PCR-RFLP were included in this survey. Eighty eight of them were stress-free (NN), twenty two were heterozygous (Nn) and four animals were stress susceptible (nn). A significant differences among the animals with different PSS genotypes appeared in the values of creatinine, bilirubine and in the enzyme activity of alkaline phosphatase (AP), lactate dehydrogenase (LDH) and creatine phoshokinase (CPK), which was previously referred. In addition, we found a correlation between aspartate aminotransferase (AST) and PSS genotypes. The values for AP, AST and LDH in stress susceptible animals were greater than the reference values and we propose that they could be used as biochemical markers for MH.